MZT Proteins Form Multi-Faceted Structural Modules in the γ-Tubulin Ring Complex.

ABSTRACT: Microtubule organization depends on the γ-tubulin ring complex (γ-TuRC), a ∼2.3-MDa nucleation factor comprising an asymmetric assembly of γ-tubulin and GCP2-GCP6. However, it is currently unclear how the γ-TuRC-associated microproteins MZT1 and MZT2 contribute to the structure and regulation of the holocomplex. Here, we report cryo-EM structures of MZT1 and MZT2 in the context of the native human γ-TuRC. MZT1 forms two subcomplexes with the N-terminal α-helical domains of GCP3 or GCP6 (GCP-NHDs) within the γ-TuRC "lumenal bridge." We determine the X-ray structure of recombinant MZT1/GCP6-NHD and find it is similar to that within the native γ-TuRC. We identify two additional MZT/GCP-NHD-like subcomplexes, one of which is located on the outer face of the γ-TuRC and comprises MZT2 and GCP2-N

SUBMITTER: Wieczorek M 

PROVIDER: S-EPMC7416306 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature